Sensitized photographic element and process of making same



Patented Apr. 9, 1935 UNITED' STATES PATENT OFFICE SENSITIZED PHOTOGRAPHIC ELEMENT AND PROCESS F MAKING SAME Leopold D. Mannes and Leopold Godowsky, Jr.,

New York, N. Y.

Applieation March is, 1930, serial No. 437,266

14 Claims.

vide a photographic element by means of which a photographic image in color may be obtained by a direct and single development.

The invention may be employed for the production of pictures in natural color byusing two colors corresponding to the two colors of a twocolor process or by using three colors corresponding to the three colors of a three-color process. Also' four or more different colors may be employed but ordinarily three colors are the maximum number required.

The invention is illustrated in the. accompanying drawing in which:

Fig. l shows diagrammatically the silver halide emuisined.

Fig. 2 shows the colored emulsion prior to exposure.

Fig. 3 shows the exposed plate or iilm.

Fig. 4 shows the developed plate or nlm; and

Fig. 5 shows the completed product with the silver removed.

The invention may also be employed for the production of pictures in a single color, that is to sayyinstead of coloring the silver .image by toning or dyeing, there may be produced by the invention a colored picture wherein the image is formed of an insoluble colored vcompound suspended in the colloidal compound forming the body of the emulsion. The invention is based on the fact that light-sensitive silver halides may be formed by precipitating them in the presence of certain organic compounds such as alpha naphthol or paranitrobenzylcyanide, these latter compounds being absorbed by or adsorbed to the silver-halide crystal or grains thus formed. When these grains, distributedin an ordinary emulsion,v

that is, suspended in a colloidal medium, are exposed in the course of the customary photographic process and developed by such ,a developer as diethyl paraphenylenediamine hydrochloride, there is formed in situ with the reduced silver image and by the local oxidation reaction of-the development a substantially insoluble colored compound which will remain suspended in whatever colloidal medium holds the halide grain. The

silver image itself furthers the reaction appar` ently by catalysis.

This process is to be distinguished from previously described processes in whichthe color-forming compound is merely dispersed, among the silver halide grains suspended in the colloid; the

silver halide grains in this case here disclosed adsorbing or absorbing the color-'forming compound in question instead of allowing it to permeate the colloid indiscriminately. This process is to be further distinguishedfrom others previously attempted in which highly colored compounds were precipitated in combination with the silver halide. An emulsionthus formed would be sufficiently absorptive to llight of certain colors, to prohibit normal penetration of incident 10 lightnecessary to correct exposure. These colorforming compounds here referred to are all sub- 'stantially colorless, especially in the minute quantlties'employed for this purpose, thus not materially affecting the normal color of an emulsion. 15

After development, the silver may beremoved p with potassium-cyanide, for instance, leaving a pure colored image. Potassium ferricyanide and hypo may be used instead of potassium cyanide.

1f a single emulsion is employed containing 20 grains of silver halide with a single absorbed or adsorbed color-former, there will be produced by the procedure described a picture in the color desired, depending on, the particular colorformer employed in the manufacture of the iilm. 25 Thus with the same developer and the same procedure of development a variety of diierent color effects may be obtained. The selection of the desired color is made by selecting the particular nlm to be'exposed. The color of the resulting 30 picture will be designated on-the film package and the user has merely to select the lm for the desired color and follow the ordinary procedure of development as above described.

The inventionmay` be employed in color pho- 35 tography in several diierent ways.

We preferably intermix a plurality of diierently color-sensitized emulsions containing respectively different color-formers and applythe mixture in a single layer to the support. A sin- 40 gle exposure followed by a single development of such a lm will cause each color record to be developed to a correspondingly different color.

For a two-color process a red-sensitive emulsion containing a silver halide precipitated with 45 trichlornaphthol or related compound and a bluegreen sensitive emulsion containing a silver halide precipitated with a nitrobenzylcyanide compound mixed with, say, ethyl acetoacetate,

are intermixed and spread on the iilm or other 50 support in a single layer. The nlm is exposed in the usual manner and developed with a developer such as diethyl paraphenylenediamine hydrochloride. Both images are thus simultaneously developed, and also there are simultanel Y veloping agent.

ouslyformed two color images corresponding to the silver images. ,The silver images are thereafter dissolved out leaving clear colored images.

A third layer maybe coated for tri-color recording consisting of an ordinary blue-sensitized (i. e. not especially sensitized) layer containing yellow illter dye, the grains of this layer containing a yellow color-former such as ethyl-acetoacetate. This compound will in such an instance be left out of the green-sensitive layer. In the case of emulsionmixtures such a third emulsion may be mixed together with the two described above.

Instead of mixing the emulsions they ma;r be

applied in separate layers, preferably with -the red-sensitive layer next the illm. No change need be made in the exposure, development and subsequent treatment of the film. 'Ihe two images will be simultaneously formed 'as before.

Similar positives may be produced by printing-` from the negatives on positive illm of the same character, with the emulsions either admixed or in separate layers, and thereafter following the same `procedure of development, etc.

The term color-former here used refers to organic compounds acting as couplers in connection with certain developers in photographic processes, thus forming colored compounds, usually insoluble in water, in the presence of the iinely divided silver being reduced by the de- 'Ihis,.in general, distinguishes them from leuca-bases and rather classiiies them as intermediate couplers in a dye-forming process. Phenols, naphthols, cresols, nitrophenylacetonitriles, ethyl acetoacetate, and their halogenated or sulphonic acid compounds are typical members of this type of color-former.

Paraphenylenediamines and paramidophenols are typical developers used in conjunction with the color-formers.

The colored compounds so formed belong to the class, for instance, of ndophenols, indoanilines, and indamines.

We claim: f

1. A light-sensitive photographic emulsion comprising a colloidal carrier containing silver halide grains, certain of said grains carrying an y absorbed or adsorbed substance adapted when subjected to the action ot a developer to produce a substantially transparent insoluble compound of a color not theretofore present in said substance suspended in a colloidal carrier.

4. The method of making a light-sensitive photographic element which consists in precipitating a silver halide in the presence of an organic color-forming compound, and thereafter distributing said precipitate in a suitable emulsion or other colloidal medium.

5. A light-sensitive photographic element which consists of a support, an emulsion thereon, said emulsion containing a plurality of different light-sensitive substances, each substance comprising a silver halide with an absorbed or adsorbed color-former, the color-formers of the different light-sensitive substances being adapted to produce different colors.

6. A silver halide grain or crystal with an absorbed or adsorbed color-forming compound.

'7. The method of producing a silver halide grain or crystal with an absorbed or adsorbed color-former, which consists in precipitating the' silver halide in the presence oi' a color-formen* 8. The method of producing a silver halide grainor crystal with an absorbed or adsorbed color-former, which consists in ripening the silver halide in the presence of a color-former.

9. A silver halide grain or crystal with an absorbed or adsorbed color-forming compound, saidV halide being also sensitized to record a particular color or set of colors.

10. The method of producing a silver halide grainor crystal with an absorbed or adsorbed color-former, which consists in precipitating the silver halide in the presence of a color-former and subjecting it to the action of a colorsensitizer.

l1. A light-sensitive grain or crystal contain-- ing silver, with a color-forming compound bound thereto by physical or chemical union.

12. The method of producing the grain or crystal of the foregoing claim which consists in precipitating the light-sensitive silver compound in the presence of a color-former.

13. A light-sensitive grain or crystal containing silver, with a color-forming compound bound thereto by physical or chemical union, said grain or crystal being sensitized to record a. particular color or set of colors.

14. The method of producing the grain or crystal of the preceding claim which consists in the precipitating of the silver compound in the presence of a color-,former and subjecting it to the action of a color-sensitizer.

LEOPOLD D. MANNES. LEOPOLD GODOWSKY, J R. 

